Pneumoconiosis

Pneumoconioses are occupational lung diseases caused by prolonged inhalation of dust and characterized by the development of diffuse interstitial fibrosis. They can be found in mining, coal, asbestos, engineering and some other industries. The development of pneumoconiosis depends on the physico-chemical characteristics of the inhaled dust.

The clinical picture of pneumoconiosis has a number of similar features: a slow, chronic course with a tendency to progress, often leading to disability; Persistent sclerotic changes in the lungs.

Common principles are the prevention of pneumoconioses, primarily the implementation of technical and sanitary measures aimed at the maximum reduction of dustiness in the air of work premises, the conduct of preliminary (upon admission to work) and periodic medical examinations. So, contraindications to employment, related to exposure to silicon-containing dust, are pulmonary tuberculosis, a number of diseases of the upper respiratory tract and bronchi, chronic diseases of the anterior segment of the eyes, skin, allergic diseases. It is mandatory to conduct periodic medical examinations 2 times a year or 1 time in 2 years, depending on the potential danger of production. Examinations are performed by a therapist, an otolaryngologist with radiography of the thoracic cavity organs, and examination of the function of external respiration. Biological methods of prevention are aimed at increasing the reactivity of the body and accelerating the removal of dust from it. Recommended general ultraviolet irradiation, the use of alkaline inhalation, general and respiratory gymnastics; Special nutrition is organized, aimed at normalizing protein metabolism and inhibiting the konyotic process.

There are the following main types of pneumoconiosis:

Silicosis and silicatoses, metalloconiosis, karboconioses, pneumoconosis from mixed dust (anthracoplise, siderosilicosis, etc.), pneumoconiosis from organic dust.

Silicosis - the most common and heavily leaking form of pneumoconiosis, develops as a result of prolonged inhalation of dust containing free silicon dioxide. Most often found in miners of various mines (drillers, slaughterers, sawmillers, etc.), workers of foundries (sandblasters, choppers, trimmers, etc.), workers in the production of refractory materials and ceramic products. It is a chronic disease, the severity and rate of development of which can be different and are directly dependent on both the aggressiveness of the inhaled dust (dust concentration, the amount of free silica in it, the dispersity, etc.), and the duration of the dust factor and Individual characteristics of the body.

Pathogenesis. Gradual atrophy of the ciliated epithelium of the respiratory tract sharply reduces the natural release of dust from the respiratory system and promotes its retention in the alveoli. Interstitial lung tissue develops primary reactive sclerosis with a steadily progressing course. The most aggressive are the particles of 1-2 μm in size, capable of penetrating into the deep branches of the bronchial tree, reaching the pulmonary parenchyma and lingering in it. A certain role is played by mechanical as well as toxic chemical damage to lung tissue, but the activity of dust depends mainly on the crystal structure and the ability of crystals to adsorb proteins, which is due to the presence of silanol groups (SiOH) on their surfaces. This causes a large death of phagocytes with the release of substances of lipoprotein nature (antigens) and the formation of antibodies entering the precipitation reaction, which underlies the formation of the silicic nodule. Progression of the fibrous process leads to a violation of blood supply, lymphostasis and further proliferation of connective tissue. All this, along with inflammatory and atrophic processes in the bronchi leads to the emergence of emphysema of the lungs, pulmonary heart and insufficiency of external respiration.

Symptoms, course. The disease develops gradually, as a rule, with a long work experience under the influence of dust. Initial clinical symptoms are meager: shortness of breath with physical exertion, chest pain of uncertain character, rare dry cough. A direct examination often does not reveal pathology. However, even in the initial stages it is possible to determine the early symptoms of emphysema, which develops mainly in the lower lateral parts of the chest, a boxed hue of percussion sound, a decrease in the mobility of the pulmonary edges and chest excursions, and a weakening of the breath. Attachment of changes in bronchi is manifested by hard breathing, sometimes with dry rales. With severe forms of the disease, dyspnea worries even at rest, chest pain increases, a feeling of pressure in the chest appears, cough becomes more permanent and is accompanied by sputum, and the severity of percussion and auscultative changes.

The main in the diagnosis of silicosis is an x-ray study. In the initial stage, the x-ray patterns show an increase and deformation of the pulmonary pattern, the appearance of cellularity and reticularity, the emergence of single shades of silicic nodes, the consolidation of the interlobar pleura; The changes are usually symmetrical, sometimes more pronounced in the right lung with predominant localization in the middle and lower divisions. Further, the deformation of the bronchial pattern is increasing, numerous numerous small-spotted irregular shapes of the shadow appear, with rounded-shaped silicic nodules with distinct contours (the "blizzard" or "shot" lungs pattern is the second stage of the disease). When the process goes to stage III, the shadows merge into large tumor-like conglomerates with the formation of cavities in some cases, more often when combined with tuberculosis; Signs of emphysema are expressed.

In accordance with clinical and radiological peculiarities, 3 forms of silicosis are distinguished: nodular, interstitial and tumor-like (nodular). The question of the possibility of reverse development of initial silicic changes has not been resolved. At the same time, silicosis is characterized by a tendency to progression even after stopping work under conditions of exposure to dust containing silicon dioxide. If an unfavorable combination of a number of factors (high dispersion and concentration, high content of free silica in the dust, severe working conditions, etc.), silicosis can develop after several months of work ("early silicosis"), which is extremely rare.

Complications of silicosis: pulmonary heart, pulmonary heart failure, pneumonia, obstructive bronchitis, bronchial asthma, less often bronchoecgatic disease. Silicosis is often complicated by tuberculosis, which leads to a mixed disease company - silicotuberculosis. In the differential diagnosis of silicosis and pulmonary tuberculosis, the absence of symptoms of intoxication with silicosis, the relative severity of complaints and physical symptoms, and the characteristic roentgenologic picture are important. The tumor-like form of silicosis differs from lung cancer by the slow evolution of shadows and the relatively good condition of the patient. Silicosis is also characterized by a change in the parameters of external respiration; Decrease in vital capacity of lungs, pneumotachometric parameters and maximal ventilation of lungs, i.e., reduction of pulmonary reserves. Important in the diagnosis of silicosis "dust" work experience and sanitary and hygienic characteristics of working conditions of the worker. The treatment is aimed at the normalization of metabolism, primarily protein, with the help of rational nutrition, saturation of the body with vitamins C, P and PP. Showing preparations of expectorant action, oxygen therapy, respiratory gymnastics; With shortness of breath, bronchodilators (theofedrine, euphyllin, aerosols of atropine, ephedrine, euspyran); With decompensation of the pulmonary heart -'- - diuretics and cardiac glycosides. In the initial stages, sanatorium treatment is shown (the Southern coast of the Crimea, Kislovodsk, kumysotherapy at the resorts of Kazakhstan, etc.).

Silicates are caused by the inhalation of dust silicates-minerals containing silica bound to other elements (magnesium, calcium, iron, aluminum, etc.). This group of pneumoconiosis includes asbestosis, talcosis, cementosis, pneumoconiosis from dust mica, etc. Silicates are widely distributed in nature and are used in many industries. Silicatosis can develop during work related to both the extraction and production of silicates, and with their processing and application. With silicates, a predominantly interstitial form of fibrosis is observed.

Asbestosis is the most common form of silicosis caused by the inhalation of asbestos dust. In the development of asbestosis, not only the chemical action of dust plays a role, but also the mechanical damage to the lung tissue with asbestos fibers. It occurs in construction, aircraft, machine and shipbuilding industry workers, as well as those engaged in the manufacture of slate, plywood, pipes, asbestos packings, brake bands and. Etc. It develops in persons with an experience of work in conditions of exposure to asbestos dust from 5 to 10 years. It manifests itself as a symptomatic complex of chronic bronchitis, emphysema of the lungs and pneumosclerosis. The sclerotic process develops mainly in the lower parts of the lungs around the bronchi, vessels, in the alveolar septa. As a rule, patients are disturbed by shortness of breath and cough. In sputum, "asbestos bodies" are sometimes found. When examined, so-called asbestos warts on the skin of the limbs are noted. X-ray in the early stages of the disease is determined by the intensification of the pulmonary pattern, the expansion of the gates of the lungs and increased transparency of their basal sections; As progression - the appearance of rough tyazhistosti. Against the background of fibrosis (it has, as a rule, cellular or mesh character), small and large-nodular shadows can be detected. At the beginning of the disease - signs of subatrophic or atrophic rhinopharyngitis, and sometimes laryngitis. A pronounced pleural reaction is typical. Of complications, pneumonia is most common. Often there is respiratory failure. Possible development of tumors with localization in the pleura, bronchi, lung (up to 15-20% of cases).

Talcosis is a relatively benign silicosis, caused by the inhalation of talc dust. Less often than asbestosis, accompanied by bronchitis syndrome, less pronounced propensity to progress. Heavy itches talcosis, caused by cosmetic powder.

Metalloconiosis is caused by the inhalation of dust from certain metals: beryllium - dust of beryllium, sideroz - dust of iron, aluminosis - dust of aluminum, barite - dust of barium, etc. Metalloconiosis, characterized by accumulation of X - ray contrast dust (iron, tin, Barium) with a moderate fibrotic reaction. These pneumoconiosis do not progress if exposure to dust from these metals is excluded; It is also possible to regress the process due to self-cleaning of the lungs from radiopaque dust. Aluminosis is characterized by the presence of diffuse, mainly interstitial fibrosis. With some metalloconiosis, the toxic and allergic action of dust with a secondary fibrotic reaction (beryllium, cobalt, etc.), sometimes with a severe progressive course, predominates. Berylliosis can manifest itself in various clinical forms: acute pneumonitis, diffuse bronchiolitis, lung granenematosis, diffuse progressive pneumosclerosis (see Hammen-Rich syndrome).

Carboconiosis is caused by exposure to carbon-containing dust (coal, graphite, soot) and is characterized by the development of moderately pronounced small-focal and interstitial pulmonary fibrosis.

Anthracosis is carcanconiasis caused by inhalation of coal dust. Developed gradually by workers with a long record of work (15-20 years) under the influence of coal dust, miners working on the extraction of coal, workers in dressing plants and some other industries. The course is more favorable than with silicosis, the fibrous process in the lungs proceeds according to the type of diffuse sclerosis. The inhalation of mixed dust of coal and rock containing silicon dioxide causes anthracosilicosis, a heavier form of pneumoconiosis, characterized by progressive development of fibrosis. The clinical and X-ray picture of anthracosilicosis depends on the content of free silica in the dust.

Pneumoconiosis from organic dust can be attributed to pneumoconiosis conditionally, since they are not always accompanied by a diffuse process with the outcome of pneumofibrosis. Bronchitis with an allergic component develops more often, which is characteristic, for example, of an abscissosis arising from the inhalation of vegetable fiber dust (cotton). When exposed to the dust of flour, grain, sugar cane, plastics, diffuse pulmonary changes of an inflammatory or allergic nature with a moderate fibrotic reaction are possible. This group also includes the "farmer's lung" - the result of exposure to various agricultural dusts with admixtures of fungi. With regard to the entire group of pneumoconiosis, it is not always possible to distinguish the etiological role of the professional dust factor and pathogenic microorganisms, especially fungi.